Steganography: a class of secure and robust algorithms

This research work presents a new class of non-blind information hiding algorithms that are stego-secure and robust. They are based on some finite domains iterations having the Devaney's topological chaos property. Thanks to a complete formalization of the approach we prove security against watermark-only attacks of a large class of steganographic algorithms. Finally a complete study of robustness is given in frequency DWT and DCT domains.Comment: Published in The Computer Journal special issue about steganograph

Are Social Networks Watermarking Us or Are We (Unawarely) Watermarking Ourself?

In the last decade, Social Networks (SNs) have deeply changed many aspects of society, and one of the most widespread behaviours is the sharing of pictures. However, malicious users often exploit shared pictures to create fake profiles, leading to the growth of cybercrime. Thus, keeping in mind this scenario, authorship attribution and verification through image watermarking techniques are becoming more and more important. In this paper, we firstly investigate how thirteen of the most popular SNs treat uploaded pictures in order to identify a possible implementation of image watermarking techniques by respective SNs. Second, we test the robustness of several image watermarking algorithms on these thirteen SNs. Finally, we verify whether a method based on the Photo-Response Non-Uniformity (PRNU) technique, which is usually used in digital forensic or image forgery detection activities, can be successfully used as a watermarking approach for authorship attribution and verification of pictures on SNs. The proposed method is sufficiently robust, in spite of the fact that pictures are often downgraded during the process of uploading to the SNs. Moreover, in comparison to conventional watermarking methods the proposed method can successfully pass through different SNs, solving related problems such as profile linking and fake profile detection. The results of our analysis on a real dataset of 8400 pictures show that the proposed method is more effective than other watermarking techniques and can help to address serious questions about privacy and security on SNs. Moreover, the proposed method paves the way for the definition of multi-factor online authentication mechanisms based on robust digital features

Side-Information For Steganography Design And Detection

Today, the most secure steganographic schemes for digital images embed secret messages while minimizing a distortion function that describes the local complexity of the content. Distortion functions are heuristically designed to predict the modeling error, or in other words, how difficult it would be to detect a single change to the original image in any given area. This dissertation investigates how both the design and detection of such content-adaptive schemes can be improved with the use of side-information. We distinguish two types of side-information, public and private: Public side-information is available to the sender and at least in part also to anybody else who can observe the communication. Content complexity is a typical example of public side-information. While it is commonly used for steganography, it can also be used for detection. In this work, we propose a modification to the rich-model style feature sets in both spatial and JPEG domain to inform such feature sets of the content complexity. Private side-information is available only to the sender. The previous use of private side-information in steganography was very successful but limited to steganography in JPEG images. Also, the constructions were based on heuristic with little theoretical foundations. This work tries to remedy this deficiency by introducing a scheme that generalizes the previous approach to an arbitrary domain. We also put forward a theoretical investigation of how to incorporate side-information based on a model of images. Third, we propose to use a novel type of side-information in the form of multiple exposures for JPEG steganography

Detection of covert Voice over Internet Protocol communications using sliding window-based steganalysis

The authors describe a reliable and accurate steganalysis method for detecting covert voice-over Internet protocol (VoIP) communication channels. The proposed method utilises a unique sliding window mechanism and an improved regular singular (RS) algorithm for VoIP steganalysis, which detects the presence of least significant bit embedded VoIP streams. With this mechanism, the detection window moves forward one packet or several packets each time to screen VoIP streams. The optimum detection threshold for the proposed detection metric is computed by modelling the distributions of the new metric for stego and cover VoIP streams. Experimental analysis reveals that the proposed method improves the detection time significantly, utilising less memory resources for VoIP steganalysis, thereby enabling real-time detection of stego VoIP streams. The proposed method also provides a significant improvement on precision in detecting multiple covert VoIP channels when compared to the conventional RS method

Data Hiding and Its Applications

Data hiding techniques have been widely used to provide copyright protection, data integrity, covert communication, non-repudiation, and authentication, among other applications. In the context of the increased dissemination and distribution of multimedia content over the internet, data hiding methods, such as digital watermarking and steganography, are becoming increasingly relevant in providing multimedia security. The goal of this book is to focus on the improvement of data hiding algorithms and their different applications (both traditional and emerging), bringing together researchers and practitioners from different research fields, including data hiding, signal processing, cryptography, and information theory, among others

Digital Copyright Protection: Focus on Some Relevant Solutions

Copyright protection of digital content is considered a relevant problem of the current Internet since content digitalization and high performance interconnection networks have greatly increased the possibilities to reproduce and distribute digital content. Digital Rights Management (DRM) systems try to prevent the inappropriate or illegal use of copyrighted digital content. They are promoted by the major global media players, but they are also perceived as proprietary solutions that give rise to classic problems of privacy and fair use. On the other hand, watermarking protocols have become a possible solution to the problem of copyright protection. They have evolved during the last decade, and interesting proposals have been designed. This paper first presents current trends concerning the most significant solutions to the problem of copyright protection based on DRM systems and then focuses on the most promising approaches in the field of watermarking protocols. In this regard, the examined protocols are discussed in order to individuate which of them can better represent the right trade-off between opposite goals, such as, for example, security and easy of use, so as to prove that it is possible to implement open solutions compatible with the current web context without resorting to proprietary architectures or impairing the protection of copyrighted digital content